Under netplan with "renderer: networkd", Update-manager claims "No network connection detected, you can not download changelog information." even network is connected

[hogetaro]

My network is cofigured under netplan using "renderer:networkd".

Update-manager claims "No network connection detected, you can not download changelog information." , even the network is connected

Even it's not a critical bug, Checking update detail with updatet-manager is sometime so convinient for me. So Ill be happy if this fixed!

It seems UpdateManager/Core/roam.py does network connectivity check ONLY with NetworkManager statu via dbus. Checking network connectivity via netplan+networkd is also expected.
(or Why not use try-and-error way?)

1) The release of Ubuntu you are using, via 'lsb_release -rd' or System -> About Ubuntu
Description: Ubuntu 20.04.1 LTS
Release: 20.04

2) The version of the package you are using, via 'apt-cache policy pkgname' or by checking in Software Center
  Installed: 1:20.04.10.1
  Candidate: 1:20.04.10.1
  Version table:
 *** 1:20.04.10.1 500
        500 http://archive.ubuntu.com/ubuntu focal-updates/main amd64 Packages
        500 http://archive.ubuntu.com/ubuntu focal-updates/main i386 Packages
        100 /var/lib/dpkg/status
     1:20.04.9 500
        500 http://archive.ubuntu.com/ubuntu focal/main amd64 Packages
        500 http://archive.ubuntu.com/ubuntu focal/main i386 Packages

3) What you expected to happen
 In Update-Manager GUI, When I select a package name in "Details of update" panel, Content of "Changes" tab should show change details of the selected package.

4) What happened instead
Content of "Changes" tab shows the message "No network connection detected, you can not download changelog information." ,Even network is connected via netplan+networkd.

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Tuomas Heino (iheino+ub)]

As a workaround for this use case may want to try

sudo systemctl stop NetworkManager.service